Seaweed Allelopathy Against Coral: Surface Distribution of a Seaweed Secondary Metabolite by Imaging Mass Spectrometry

• Type of Material: Article
• Authors: Tiffany D. Andras, Georgia Institute of Technology; Troy S. Alexander, Georgia Institute of Technology; Asiri Gahlena, Georgia Institute of Technology; R. Mitchell Parry, Georgia Institute of Technology; Facundo M. Fernandez, Georgia Institute of Technology; Julia Kubanek, Georgia Institute of Technology; Dongmei Wang, Emory University; Mark E. Hay, Georgia Institute of Technology
• Language: English
• Date: 2012-10-01
• Publisher: Springer Verlag (Germany)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 Springer Science+Business Media New York.
• Final Published Version (URL): http://dx.doi.org/10.1007/s10886-012-0204-9
• Title of Journal or Parent Work: Journal of Chemical Ecology
• ISSN: 0098-0331
• Volume: 38
• Issue: 10
• Start Page: 1203
• End Page: 1214
• Grant/Funding Information: Support came from the National Science Foundation (OCE 0929119); the National Institutes of Health (U01-TW007401); and the Teasley Endowment to the Georgia Institute of Technology.; FMF acknowledges support from ARRA NSF MRI Instrument Development grant #0923179.
• Keywords: Porites; Surface; Seaweed-coral interactions; CARIBBEAN CORALS; RESILIENCE; REEF COMMUNITY; LARVAL SETTLEMENT; CHEMICAL DEFENSE; ALGA CALLOPHYCUS-SERRATUS; Biochemistry & Molecular Biology; CLIMATE-CHANGE; PHASE-SHIFTS; Seaweed; Phacelocarpus; DESORPTION ELECTROSPRAY-IONIZATION; Marine; Coral reefs; Environmental Sciences & Ecology; Ecology; NATURAL-PRODUCTS; Life Sciences & Biomedicine; Science & Technology
• Research Categories: Engineering, Biomedical; Biology, Ecology

Abstract

Coral reefs are in global decline, with seaweeds increasing as corals decrease. Although seaweeds inhibit coral growth, recruitment, and survivorship, the mechanism of these interactions is poorly understood. Here, we used field experiments to show that contact with four common seaweeds induces bleaching on natural colonies of Porites rus. Controls in contact with inert, plastic mimics of seaweeds did not bleach, suggesting seaweed effects resulted from allelopathy rather than shading, abrasion, or physical contact. Bioassay-guided fractionation of the hydrophobic extract from the red alga Phacelocarpus neurymenioides revealed a previously characterized antibacterial metabolite, neurymenolide A, as the main allelopathic agent. For allelopathy of lipid-soluble metabolites to be effective, the compounds would need to be deployed on algal surfaces where they could transfer to corals on contact. We used desorption electrospray ionization mass spectrometry (DESI-MS) to visualize and quantify neurymenolide A on the surface of P. neurymenioides, and we found the molecule on all surfaces analyzed, with highest concentrations on basal portions of blades.